Study Art! Then learn 3D, it propel you.
+1
edit: Most of the 3D stuff, you can learn yourself but when you really want to advance(expert/master level) and specialize, then I'd recommend taking some courses.
When I started, I first wanted to go to a school specialized on that topic, but I didn't have the money and I was one year too old for the government paying the bill.
I was interested in that topic all my life and decided to just start by myself. bought two books, a learning license through a friend and played around. Tried to recreate everything I saw in the media. It took about two or three years of that more or less unguided but fun approach until I was ready to create something that I wouldn't feel ashamed to show off. If you have a real passion and there's a problem, then it doesn't matter if it takes 14-16hours to solve it.
Later then I did a certificate program which wasn't really worth the money and a bit later some courses on Ryan Kingslien's site. They recently changed to
Artist Awake. There I did "Character Design For Film And Games with Danny Williams". Youtube videos won't help you much and that $500 is much better spent on an industry veteran teaching and reviewing your work. You'll also learn tricks that many don't know and make your workflow much more efficient.
Nowadays, they have courses on pretty much every single subject related to 3D and some of them, especially introduction classes are for free.(Maya, Unreal, etc.)
Later then I focused more on art. Colors, light & shadow, composition, symmetry... many "tiny" things that seem negligible at first but have a huge impact on the final image.
But as mentioned: Art and if you have some spare time, download a free 3D app like Blender, watch an introduction to the GUI and play around while doing the other. Assuming you have the time. You have plenty of time to decide what field you want to go to(and there are many). After all, you'll need to learn the fundamentals first.
And don't forget Photoshop. It'll be the last 10% of your work and decide how good the final image will be.